1. Technical Field
This invention relates generally to a method and apparatus for route navigation between an origin and a destination, and more specifically to generating a plurality of possible navigation routes and processing each navigation route to select a less environmentally harmful navigation route for presentation to a user.
2. Background Art
Navigation systems, be they vehicular, handheld, embedded in an electronic device, or other, are devices that provide maps and navigation instructions to a user so the user can travel from an origination location to a destination location. Some navigation devices include a proximity detection device, such as a Global Positioning System (GPS) receiver, which can determine the current location of the system using GPS satellites. Using map data located either on the device or in a remote map server, the navigation system can display a map and navigation instructions to the user.
It is generally the case that multiple routes exist between any given origin and destination. For example, there may be one route along surface streets while another route passes along the highway. One route may pass through commercial districts, while another route passes through bypass roads, and so forth.
Many prior art navigation systems are configured to select an optimal route based upon time or distance. For example, where multiple routes exist, many navigation systems simply calculate the distance to be traversed along each route and select the shortest route for presentation to the user. This is often less than ideal in that a selected route may take longer to traverse than other longer routes due to traffic, traffic signals, accidents and so forth. Other navigation systems use speed limit information to determine a shortest time along each route. However, these systems fail to provide any advantage over the distance based systems as they often fail to consider traffic congestion, accidents, number of traffic signals or intersections, and so forth.
The problem with each of these prior art navigation systems is that the presume time is the highest priority interest when selecting a navigation route from multiple navigation routes. However, for many people time is not the foremost consideration. Other factors are more important.
There is thus a need for an improved navigation system and corresponding method for presenting navigation routes selected based upon criteria other than time or distance.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.